It is now official. The true identity of GoogleGuy has been reveal by the Guy himself. It won't come as a surprise to most people in the industry, because it was all but certain by this point. Matt Cutts is GoogleGuy.
Danny Sullivan report that the admission came at a recent Search Engine Strategies (SES) conference:
I moderated the panel, and the confession came out when a member of the audience flat out asked Matt if he was GoogleGuy. Matt hesitated just a moment, and I could swear I could almost hear the internal debate of "should I finally confess or not." And then he did, saying as Rand notes that he sort of backed into being the GoogleGuy who posts on forums and blogs. Matt then added that today, GoogleGuy might be one of many different people from Google commenting in public areas.
For the past several years, many people have strongly believed that Matt Cutts was GoogleGuy, to the point of feeling certain of it. Still, to my knowledge, it wasn't "proven", and until now, he has not made a public admission. For for what its worth, it is now official: Matt Cutts is GoogleGuy.
Or maybe its not official?
In a postscript to the Search Engine Watch article, it is mentioned that Matt Cutts has disputed the reported admission over on the seomoz blog, saying:
I didn't take the question as "Are you GoogleGuy?". I took the question as "How did you end up doing a bunch of webmaster communication duties?". Maybe I misheard the question though.
So there you go. You can decide for yourself. ;)